Investigating the hydrodynamics of free-surface flow over rippled seabeds remains a key focus due to the presence of multiple underwater sandbars and ambient currents in coastal and estuarine regions. There has been growing interest in the free-surface responses induced by resonant wave-current-bottom interactions. These interactions have the potential to transfer the wave energy from ambient flow to free-surface waves along with their intensive instability behaviors. The intensive resonant behaviors are closely related to the resonant conditions. If the wave-current conditions deviate from the exact resonance (also called the detuning scenarios), the free-surface responses will be affected significantly. However, the kinematic responses of the detuning effects are still limited and need further investigation. In this study, the detuning effects are studied based on the theoretical analysis. Two typical detuning scenarios are analyzed, and the corresponding temporal evolution/spatial distribution solutions of the near-resonant conditions are derived. Then, the phase-resolved wave hydrodynamic numerical model based on the high-order spectral method is applied to calculate the detuning behavior for cross-validation with the theoretical solutions. Finally, the detuning behaviors under near-resonant conditions are analyzed to reveal the significant quantitative decline pattern of resonant wave amplitude and period.